1. Field of the Invention
The present invention relates generally to both a system and method for determining the composition of an off-gas from a solution nuclear reactor (e.g., an Aqueous Homogeneous Reactor (AHR)) and the composition of the fissioning solution from those measurements. In one embodiment, the present invention utilizes at least one quadrupole mass spectrometer (QMS) in a system and/or method designed to determine at least one or more of: (i) the rate of production of at least one gas and/or gas species from a nuclear reactor; (ii) the effect on pH by one or more nitrogen species; (iii) the rate of production of one or more fission gases; and/or (iv) the effect on pH of at least one gas and/or gas species other than one or more nitrogen species from a nuclear reactor. In another embodiment, the present invention utilizes at least one quadrupole mass spectrometer (QMS) in a system and/or method designed to determine in real-time at least one or more of: (i) the rate of production of at least one gas and/or gas species from a nuclear reactor; (ii) the effect on pH by one or more nitrogen species; (iii) the rate of production of one or more fission gases; and/or (iv) the effect on pH of at least one gas and/or gas species other than one or more nitrogen species from a nuclear reactor.
2. Description of the Related Art
Quadrupole mass spectrometers (QMSs) are known in the instrument arts. For example, U.S. Pat. No. 4,039,828 discloses a quadrupole mass spectrometer enclosed by a high vacuum container and including an ionization chamber.
QMSs have been used in conjunction with a variety of advanced technologies. U.S. Pat. No. 5,313,067 utilizes a QMS to aid in ion processing. U.S. Pat. No. 5,411,722 employs a QMS to help homogenize and down-blend highly enriched uranium metal. United States Patent Application Publication No. 2006/0101859 utilizes a QMS to measure the off-gases from glass melting.
Traditional nuclear reactors (heterogeneous nuclear reactors) produce gas in a variety of ways; two important ways are through radiolysis and fissioning. Radiolysis is the decomposition of water by radiation. In traditional nuclear reactors, radiolytic gases are generated by particles with low rates of linear energy transfer (LET) like gamma- and beta-radiation.
In most nuclear reactors, the primary radiolytic gases of interest are hydrogen and oxygen. As is known to those of skill in the art, these gases must be managed by sub-systems within the reactor. One such sub-system may be found in U.S. Pat. No. 3,788,813. Additionally, one or more nitrate compounds can be produced when a nitrate-based fuel is utilized. In the case where one or more nitrate compounds are present, the possibility of nitrate radiolysis occurring is a certainty, thereby yielding one or more nitrogen-bearing gases (e.g., N2, NO, NO2, N2O, HNO3, particulate NO3−, particulate NH4+, and/or NH3).
Nuclear fission also produces gases directly. Appropriately, these gases are called fission product gases and include, but are not limited to, noble gases, such as xenon (Xe) and krypton (Kr), as well as cesium (Cs) and various iodine (I) species. In heterogeneous reactors, these gases are generally retained by the fuel cladding. However, when fuel cladding fails, these gases escape into the rest of the system. Methods have been developed to detect these leaks (see, e.g., U.S. Pat. No. 3,632,470). These fission gases are fairly easy to detect using radiation detectors. Currently, commercial-off-the-shelf equipment is used to detect these gases both locally and in facility off-gas lines. These methods are routine and common-place throughout the nuclear industry.
Given the above, a need exists in the art for a system and method for determining the composition of the off-gas from a solution nuclear reactor and the composition of the fissioning solution from those measurements.